The answer

In order to get a good start, yeast requires oxygen for initial growth. If it doesn't have enough oxygen initially, it will take a long time for the brew to ferment. There are probably thousands of yeasts to choose from. You can find a list on this site: http://www.wyeastlab.com/beprlist.htm.

Add to or comment on this answer using the form below.

Name: (required)

E-mail (required if you would like a response)

Comments

Note: All submissions are moderated prior to posting.

If you found this answer useful, please consider making a small donation to science.ca.